Hi,
This is for one octet, but is there a step-by-step checklist for one
you have difference in more octets. How you can come to exactly how many
entries, and what they are? I looked through the BLS videos and they
helped a bit. Its more when you are presented with a list of multiple
entries, how do you start?
Sincerely,
Kim Pedersen
desmond Black wrote:
Good explantion man!!
----- Original Message -----
From: "Bryan Bartik"
To: "JEREMY FURR (RIT Student)"
Cc: [email protected]
Subject: Re: [OSL | CCIE_RS] ACL Wildcards
Date: Fri, 5 Jun 2009 21:50:00 -0600
I don't know of any books but there is a video in the R&S Blended
Learning Solution with some examples and exercises. This is how I
do it:
Focusing on your third octet you have
5
10
13
14
In binary that is:
0000 0101
0000 1010
0000 1101
0000 1110
We will not be able to use a one-line ACL with this. The only way
a one line ACL can match only 4 networks is if the the number of
differing bits is 2 (2^2 = 4). In this case we have 4 differing
bits, so the least amount of networks we could match with a
one-line ACL would be 2^4=16. But we may be able to break it into
2 ACLs.
5 and 13 only differ in one bit (bit 3)
10 and 14 only differ in one bit (bit 2)
So we can use 1 ACL line for each. Here is 5 and 10:
0000 0101
0000 1101
---------------
0000 0101 AND = 5
0000 1000 XOR = 8
192.168.5.0 0.0.8.0
Now for 10 and 14
0000 1010
0000 1110
---------------
0000 1010 AND = 10
0000 0100 XOR = 4
192.168.10.0 0.0.4.0
So you would have a 2 line ACL
192.168.5.0 0.0.8.0
192.168.10.0 0.0.4.0
-hth
On Fri, Jun 5, 2009 at 8:11 AM, JEREMY FURR (RIT Student)
<[email protected] <mailto:[email protected]>> wrote:
Does anyone know of a website or book that explains well how
ACL wildcards work? I have been trying to filter out four
blocks from a bunch of route advertisments but just can't get
the three I want through, this is what I have R2
is originating 192.168.2.0/24 <http://192.168.2.0/24> through
192.168.15.0/24 <http://192.168.15.0/24> in RIP to R1. I want
to only accept blocks 192.168.5.0, 192.168.10.0, 192.168.13.0
and 192.168.14.0
If I use acl with 192.168.10.0 0.0.4.0, I will get 10 and 14
but not thirteen. For the 5 network I just use the 192.168.5.0
0.0.0.255.
Any thoughts or help would be appreciated.
Jeremy Furr
[email protected] <mailto:[email protected]>
--
Bryan Bartik
CCIE #23707 (R&S), CCNP
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
Desmond Black,
In Pursuit of CCIE!!
India
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